SoFi Coding Interview Questions
25 SoFi coding interview problems with full optimal solutions — 13 easy, 10 medium, 2 hard. Every problem ships with multiple approaches (brute-force first, then the optimal), complexity tables for each, company-specific tips on what an SoFi interviewer values, and a FAQ section.
Showing 10 problems of 25
- #14mediumfoundational
14. Add Two Numbers
Add two numbers represented by linked lists in reverse order — SoFi loves this because manual carry propagation is identical to multi-period loan amortization with monthly carry-overs.
- #15mediumfoundational
15. Longest Substring Without Repeating Characters
Find the length of the longest substring with all unique characters — SoFi uses this to test sliding-window mechanics that show up in time-window risk scoring.
- #16mediumfoundational
16. Container With Most Water
Find two lines that form the largest water-holding container — SoFi uses this two-pointer classic to test whether candidates can reason about monotonic invariants.
- #17mediumfoundational
17. 3Sum
Find all unique triplets that sum to zero — SoFi uses this as a litmus test for de-duplication mechanics that appear in trade-allocation reconciliation.
- #18mediumfoundational
18. Group Anagrams
Group strings that are anagrams of each other — SoFi uses this to see if you can pick the right canonical key, a common move in transaction-categorization pipelines.
- #19mediumfoundational
19. Merge Intervals
Merge all overlapping intervals — SoFi uses this constantly because loan-statement billing periods and recurring transaction windows are interval problems in disguise.
- #20mediumfoundational
20. Unique Paths
Count the number of distinct paths from top-left to bottom-right in an m x n grid moving only right or down — SoFi uses this DP warm-up because it's structurally identical to counting investment-portfolio rebalancing paths.
- #21mediumfoundational
21. Word Search
Determine if a word can be constructed in a 2D board by walking adjacent cells without reuse — SoFi uses this DFS/backtracking classic to test recursion-with-rollback intuition.
- #22mediumfoundational
22. Coin Change
Return the minimum number of coins needed to make up a given amount — SoFi loves this because it mirrors how a loan-amortization engine selects the smallest set of payments to clear principal.
- #25mediumfoundational
25. Longest Increasing Subsequence
Find the length of the longest strictly increasing subsequence in an integer array — a classic DP problem SoFi applies to modeling loan amortization schedules and sequential credit score trends.